ИСТИНА

Oxophosphates with bismuth and transitional metals are interesting because of the wide technological applications as battery materials, sorbents, catalysts, ion-exchanges, etc. Among them copper and nickel phosphates with alkaline metals can be potential magnetic materials. Many of these compounds belong to the Bi2O3−MO−X2O5 ternary system (M = divalent metals; X = P, As, V). The new oxophosphates (fig.): [O2Bi3]O(PO4) (I), Ni(BiO)2(PO4)(OH) (II), KBi4{Ni2O4(PO4)3} (III) and Rb2Cu6Ca(PO4)4O2 (IV) were synthesized by a hydrothermal method (T = 690-700К, P = 480-500 atm) in the systems: (I, II, III) Bi(OH)3–NiCO3– K2CO3–K3PO4, (IV) CaOH)2–CuCl2– RbCl–B2O3–Rb3PO4 and studied by single-crystal X-ray diffraction. The structures were refined in the anisotropic approximation of the atomic displacement parameters to final R1 = 0.0410(I), 0.0409(II), 0.0576(III), 0.0502(IV). The new bismuth oxophosphate [O2Bi3]O(PO4) (I) (a = 5.684 Å, b = 7.033 Å, c = 9.158 Å, α= 78.96°, β=77.86°, γ=68.99°, sp.gr. P , Z=2) is the phase derivative from [O4Bi5]О0.5(PO4)2 with fluorite-like structure and ionic conductive properties. The nickel, bismuth oxophosphate Ni(BiO)2(PO4)(OH) (II) (a = 6.322 Å, b = 6.904 Å, c = 7.564 Å, α= 90.48°, β=107.22°, γ=110.76°, sp.gr. P , Z=1) with namibite type structure contains infinite chains {Ni(OH)(PO4)}∞ built of corner-sharing NiO6 octahedra. The new layer potassium, bismuth, nickel oxophosphate KBi4{Ni2O4(PO4)3} (III) (a = 13.632 Å, b = 19.610 Å, c = 5.438 Å, sp.gr. Pnma, Z=4) is expected to be paramagnetic with very weak antiferromagnetic exchange interactions.The compound Rb2Cu6Ca(PO4)4O2 (IV) (a = 16.891 Å, b = 5.641 Å, c = 8.359 Å, β = 93.92°, sp.gr. Cc, Z=2) crystallizes in a shchurovskyite type